#!/usr/bin/env node

const {Readable} = require('stream');
class MyReadable extends Readable{
  constructor(){
    super();
  }
  _read(){
    this.push(String.fromCharCode(this.#c++));
    if(this.#c>'z'.charCodeAt(0) )this.push(null);
  }
 #c = 'a'.charCodeAt(0);
}
